Weight Loss Drugs and Your Heart

While anti-obesity medications are beneficial to heart health in some ways, some drugs like Wegovy (Semaglutide), may also increase your heart rate and cause other cardiovascular issues.

Even though several older medications for weight loss (those that have been on the market for at least a decade, and those that have been pulled from the market) have known serious side effects, it hasn’t been until 2016 that the specific cardiovascular effects of the newer weight loss medications have been acknowledged, reviewed, and summarized by cardiovascular experts.

The anti-obesity medications that have been approved by the U.S. Food and Drug Administration (FDA) since 2010 have been of great interest to and a topic of ongoing debate in the cardiology community. Obesity is a known risk factor for cardiovascular disease, and lifestyle changes have long been the mainstay as the first line of therapy.

In people in whom lifestyle changes are not enough to induce a sufficient amount of weight loss to make a healthful impact, or in those who have been unable to implement recommended lifestyle changes like a healthy diet and exercise, anti-obesity medications may have a role.

However, these medications may come with cardiovascular risks. That said, if you take anti-obesity medication, it's important to monitor your heart rate and work with your healthcare provider to assess your health.

This article discusses the cardiovascular risks and benefits associated with weight loss drugs.

Benefits of Anti-Obesity Medication

With the American Medical Association (AMA) officially designating obesity as a disease in 2013, over a third (35%) of U.S. adults became the bearers of the latest chronic disease to be associated with increased risk for cardiovascular disease.

Lifestyle changes, such as healthy dietary changes and more physical activity, are still the preferred first-line strategy for losing weight. However, many people with obesity have found it difficult to achieve adequate weight loss through lifestyle changes alone. This is where weight loss drugs can help.

However, as with any drug, there are side effects to consider. For some people, the benefits of weight-loss drugs outweigh the potential risks.

Effects of Saxenda (Liraglutide)

Saxenda (liraglutide) was approved by the FDA in 2014 as a treatment option for chronic weight management in adults. In 2020, it was approved for use in children aged 12 to 17 years. Saxenda is marketed by Novo Nordisk, Inc.

This drug belongs to a larger class of drugs, known as glucagon-like peptide-1 (GLP-1) receptor agonists, which was originally introduced for the treatment of type 2 diabetes. The version of Saxenda (liraglutide) that is used for the treatment of diabetes is actually a lower dose of liraglutide. It is marketed under the brand name Victoza.

Both Victoza and Saxenda increase the sensitivity of pancreatic cells to glucose, allowing the pancreas to function more effectively in removing glucose (sugar) from the bloodstream. However, Saxenda also delays gastric emptying, which may aid in weight loss.

In clinical trials, those who used Saxenda experienced a small drop in systolic blood pressure (approximately 2.8 millimeters of mercury) and an increase in heart rate (3 beats per minute).

It should be noted that, for now, clinical trials such as the SCALE Maintenance trial, which was reported in the International Journal of Obesity in 2013, have found serious cardiac events (like heart attack and cardiac death) to be rare with Victoza/Saxenda. In fact, such serious events were actually lower in the Victoza/Saxenda group than in the placebo group (those not taking Victoza/Saxenda).

In the SCALE Maintenance trial itself, there was only one death due to heart failure, and that death occurred in the placebo group; the study participants who were taking Victoza/Saxenda had no serious cardiac events at all.

Perhaps most impressive, in the LEADER trial, the cardiovascular results of which were reported online in the New England Journal of Medicine in June 2016, approximately 9,300 patients with diabetes who were at high risk for cardiovascular disease were examined, and after five years, those who were taking Victoza had a lower rate of death due to cardiovascular disease, as well as lower rates of heart attack and stroke.

From such results, many experts are considering more seriously the likelihood that Victoza may actually help prevent cardiovascular disease in patients with diabetes. Studies looking at the effects of Saxenda at the 3-milligram dose suggest it may provide similar cardiovascular health benefits.

Effects of Wegovy and Ozempic (Semaglutide)

Wegovy (semaglutide) was approved by the FDA on June 4, 2021 for chronic weight management in those with at least one weight-related condition (such as high blood pressure, type 2 diabetes, or high cholesterol). It is marketed by Novo Nordisk, Inc.

Semaglutide was first marketed at lower doses—under the brand name Ozempic—for the treatment of type 2 diabetes. Wegovy, like Saxenda, is a (GLP-1) receptor agonist.

In clinical trials, Wegovy was shown to be associated with an increased heart rate at rest. This may be of concern, especially for those at risk of developing certain arrhythmias.

Because Wegovy also causes a delay in gastric emptying, it may have the potential to affect the absorption of other oral medications, including those used to treat heart conditions.

On March 8, 2024, Wegovy was approved by the FDA to help reduce the risk of serious heart problems in adults with either obesity or overweight. The SELECT trial, found that those who received a weekly 2.4 mg dose of semaglutide had a 20% reduction in major adverse cardiovascular events.

Effects of Contrave (Naltrexone/Bupropion)

Contrave (naltrexone/bupropion) was approved by the FDA on September 10, 2014, for the treatment of obesity. It is marketed by Orexigen Therapeutics, Inc., and contains two medications within one pill: naltrexone and bupropion.

Naltrexone, used alone, was originally approved by the FDA as a treatment for opioid addiction and alcohol dependence. Bupropion used alone, has been approved and used for the treatment of depression, seasonal affective disorder (SAD), and smoking cessation.

Together in the extended-release tablet of Contrave, however, the two medications combine to cause weight loss.

Both of these medications have previously been found to have side effects that involve the heart and cardiovascular system. In particular, the effects of Contrave on heart rate and blood pressure appear to be unfavorable. In clinical trials, Contrave was found to increase both blood pressure and heart rate.

On the other hand, the effects of Contrave on the cholesterol profile have been found to be rather favorable, with increases seen in HDL cholesterol (commonly called the “good” cholesterol) and decreases in both LDL cholesterol (the “bad” cholesterol) and ​triglycerides (fatty acids in the blood).

Some studies have suggested that Contrave does not increase the risk of major adverse cardiac events. However, more research is needed to determine if Contrave changes your risk of heart problems or stroke or of death (due to these heart conditions).

Effects of Qsymia (Phentermine/Topiramate)

Qsymia (phentermine/topiramate) was approved for use in adults by the FDA in 2012 and is marketed by VIVUS. Like Contrave, it also contains two medications within one pill: phentermine and topiramate. In 2022, Qsymia was approved for used in patients over 12 years old.

Phentermine by itself can suppress appetite and increase bodily energy expenditure, thereby resulting in weight loss. In fact, phentermine is not a new drug for this purpose, as it was approved in 1959 by the FDA for the short-term treatment of obesity. It has traditionally been limited by certain side effects, however, given that its mechanism of action involves increasing norepinephrine (adrenaline) levels in the body.

Topiramate, on the other hand, has a somewhat unclear mechanism of causing weight loss, with several pathways being postulated, including separate reductions in appetite and fat tissue. Topiramate alone, used at a higher dose than the dose that appears in Qsymia, can cause weight loss of 2.2% to 5.3% of initial body weight.

Qsymia combines both phentermine and topiramate in a single pill and at lower doses than either drug used alone. Qsymia was tested in four clinical trials, and in the end, due to its cardiac side effects, the FDA mandated that information appears on its label stating that its use is not recommended in patients with recent or unstable heart disease.

The cardiac side effects that have been of concern with this medication combination include higher heart rates, with a specific concern for the development of tachycardia (rapid heart rhythm) in certain patients. However, their effect on cardiovascular (CV) outcomes is still uncertain.

Preventing Heart Problems While on Anti-Obesity Medication

If you are taking anti-obesity medication and you experience any cardiac side effects or other adverse effects, let your medical provider know immediately. It's also important to let them know your full medical history—especially if you have any history of cardiovascular disease, such as high blood pressure, heart disease, or stroke.

Be sure to monitor your blood pressure and heart rate (pulse) while taking these medications, and let a healthcare professional know if you notice any significant changes.

Summary

While anti-obesity medications can aid in weight loss, they can also affect your heart rate and cardiovascular health. Depending on the medication, side effects may include increased heart rate and blood pressure. However, drugs like Wegovy may actually help reduce the risk of cardiovascular death, heart attack, and stroke in persons with cardiovascular disease and either obesity or overweight.

If you experience adverse affects while taking weight-loss medications, talk to your healthcare provider so you can determine whether or not to keep taking it. They may be able to recommend a different medication or treatment plan that works best for you.